It is known in the field of crop harvesting equipment to employ harvesting headers to cut crops for various purposes, such as feeding a combine harvester or swathing crop material. Such harvesting headers may comprise a cutter bar assembly for cutting the crop material, and a draper deck assembly for transporting the cut crop material to a desired location (e.g. the intake for a combine harvester). The draper deck assembly normally comprises two spaced-apart rollers for receiving a continuous loop of draper fabric or canvas, with a support plate fixed under the upper run of draper canvas and disposed between the rollers. In operation, the implement is driven into the standing crop, with the cutting edge assembly at the leading edge of the implement. After the cutting edge assembly cuts the crop material, the crop material falls and/or is moved rearwardly onto the generally horizontal draper deck assembly and then transported perpendicular to the direction of travel by the draper deck assembly and deposited either on the ground or at an intake for subsequent processing. Such an arrangement has many known benefits and has achieved wide acceptance and use.
However, it has been recognized that traditional cutter/draper arrangements as described above may generate undesirable results. In the traditional arrangement, the cutter bar assembly is slightly spaced from the draper deck assembly, and the gap between the two assemblies can receive chaff, mud, plant juices and other materials that can accumulate on surfaces adjacent the gap and ultimately interfere with optimal operation of the implement.
Some attempts have been made to address this problem by sealing the gap between the cutter bar assembly and the draper deck assembly. In one such attempt, for example, a John Deere Model 800 header was provided with a sealing plate mounted on the cutter bar assembly and extending rearwardly over the forward edge of the draper deck assembly. However, it has been recognized that the draper canvas can become pinched between the sealing plate and the support plate underlying the draper canvas, resulting in wear, and it has been noted that accumulation of undesirable materials was still evident.
In response to this identified deficiency, an alternative solution was proposed in Canadian Patent No. 2,138,939 to MacDon Industries Ltd. In this alternative solution, the support plate and rollers were shifted rearwardly of the leading edge of the draper canvas, resulting in a cantilevered edge of the draper canvas that could be in contact with an overhanging sealing plate without binding against the support plate in operation. However, there is an obvious lack of support for the forward edge of the draper canvas, with the risk that undesirable materials can still foul the moving parts of the implement.
What is needed, therefore, is a solution that provides a reliable seal and does not detract from the integrity of the draper canvas functionality.